How I currently perceive Mason's Pet Theory.
"The trajectory from the SN through JFK's neck and travelling
on a 14 degree right to left 18 degree downward path could
easily have gone to the left side of JBC."
60-degree twist for JBC. (Mason thinks this is "JBC turned right as he is at z185-z200".)
"if you move JBC a bit right and if you move JFK two inches farther
left so his rib cage is not pressing against the side of the car"
OK, JFK moved left two inches (though in my model, his rib cage is not up against the car interior). When Mason says "move JBC a bit right", he means more than a bit.
"hit the left thigh if it was out to the left as it likely was
(he would not sit as you have him with his legs together)"
How do you know that? Hee hee. More likely both knees were towards the car door as he spent much of his time looking to his right.
Please note that 24" between wounds refers to the "point-to-point distance between Kennedy's neck and the part of Connally's back that was wounded was determined photogrammetrically in the Croft photograph to be approximately 60 centimeters" (6 HSCA 54 ). 60 cm is 23 5/8", so rounded to 24. In my graphic above, there is a 24" distance from the black "wound" dots of JFK and JBC. The JBC drawing is a posterior view from the HSCA and has been flipped, so the back wound is on camera left. The scapulas are not on Connally's chest.
Simpler Version: